Global Validation

Implement comprehensive validation on both client and server sides with specific error messages and sanitization to prevent security vulnerabilities. When implementing form validation, input checking, or data sanitization. When working on API endpoints, form handlers, or data processing functions. When validating user input, business rules, or data integrity constraints. When implementing client-side validation for user experience or server-side validation for security. When checking data types, formats, ranges, or required fields. This skill applies to validation logic across all types of code files to ensure data integrity and security.